McIver David J, VanLeeuwen John A, Knafla Anthony L, Campbell Jillian A, Alexander Kevin M, Gherase Mihai R, Guernsey Judith R, Fleming David E B
University of Prince Edward Island, 550 University Ave., Charlottetown, PE, C1A 4P3, Canada. Harvard Medical School, 25 Shattuck St., Boston, MA 02115, USA. Boston Children's Hospital, 300 Longwood Ave., Boston, MA 02115, USA.
Physiol Meas. 2015 Dec;36(12):2443-59. doi: 10.1088/0967-3334/36/12/2443. Epub 2015 Nov 4.
A new portable x-ray fluorescence (XRF) screening tool was evaluated for its effectiveness in arsenic (As) quantification in human finger and toe nails ([Formula: see text]). Nail samples were measured for total As concentration by XRF and inductively coupled plasma-mass spectrometry (ICP-MS). Using concordance correlation coefficient (CCC), kappa, diagnostic sensitivity (Sn) and specificity (Sp), and linear regression analyses, the concentration of As measured by XRF was compared to ICP-MS. The CCC peaked for scaled values of fingernail samples, at 0.424 (95% CI: 0.065-0.784). The largest kappa value, 0.400 (95% CI: -0.282-1.000), was found at a 1.3 μg g(-1) cut-off concentration, for fingernails only, and the largest kappa at a clinically relevant cut-off concentration of 1.0 μg g(-1) was 0.237 (95% CI: -0.068-0.543), again in fingernails. Analyses generally showed excellent XRF Sn (up to 100%, 95% CI: 48-100%), but low Sp (up to 30% for the same analysis, 95% CI: 14-50%). Portable XRF shows some potential for use as a screening tool with fingernail samples. The difference between XRF and ICP-MS measurements decreased as sample mass increased to 30 mg. While this novel method of As detection in nails has shown relatively high agreement in some scenarios, this portable XRF is not currently considered suitable as a substitute for ICP-MS.
一种新型便携式X射线荧光（XRF）筛查工具在人手指甲和脚趾甲中砷（As）定量分析的有效性方面进行了评估（[公式：见正文]）。通过XRF和电感耦合等离子体质谱法（ICP-MS）测量指甲样本中的总砷浓度。使用一致性相关系数（CCC）、kappa值、诊断敏感性（Sn）和特异性（Sp）以及线性回归分析，将XRF测量的砷浓度与ICP-MS进行比较。CCC在指甲样本的标度值处达到峰值，为0.424（95%置信区间：0.065 - 0.784）。仅在指甲中，最大kappa值为0.400（95%置信区间： - 0.282 - 1.000），对应截止浓度为1.3 μg g⁻¹，而在临床相关截止浓度1.0 μg g⁻¹时，最大kappa值为0.237（95%置信区间： - 0.068 - 0.543），同样是在指甲中。分析总体显示XRF具有出色的敏感性（高达100%，95%置信区间：48 - 100%），但特异性较低（同一分析中高达30%，95%置信区间：14 - 50%）。便携式XRF在指甲样本作为筛查工具方面显示出一定潜力。随着样本质量增加到30 mg，XRF和ICP-MS测量之间的差异减小。虽然这种在指甲中检测砷的新方法在某些情况下显示出相对较高的一致性，但目前这种便携式XRF不被认为适合替代ICP-MS。
